A consistent stream of technological developments has changed the way people listen to and enjoy audio and musical performances. For example, sound digitization has provided a way for large volumes of sound information to be stored on a small, light package known as a compact disk (CD). It is now possible for people to have home sound systems that rival even the best theater systems.
FIG. 1 shows a top view of a listening room 100 containing typical music processing equipment including a music source 102, an amplifier 104 and four speakers 106. The music source 102 is a compact disc (CD) player, but could be another type of source, like a cassette tape player. The music source 102 couples to the amplifier 104 so that music received by the amplifier 104 can be amplified and transmitted over cables 108 to the speakers 106. A listener 110 is located approximately at the center of the listening room so that the four speakers are roughly the same distance away. The speakers are designated as front left (FL), front right (FR), rear left (RL), and rear right (RR).
When music is played through the speakers it is possible for the listener 110, who is facing front, to perceive spatial positions relating to sound components within the music. For example, the listener 110 may perceive that a singer's voice 112 is directly in front of him. The listener may also perceive that the sound of a piano 114 is to his front and right, and that the sound of a guitar 116 is behind and to the left. Although FIG. 1 depicts the spatial position of musical instruments, it is also possible to perceive spatial positions for other sound generating objects. For example, spatial positions for the sound of an automobile engine or the sound of the ocean may also be perceived using the listening room 100 as show in FIG. 1.
However, a significant problem exists in that the spatial positions and sound qualities of the sound components in a recording, such as on a CD, are determined when the recording is created. Thus, it may not be possible for the sound components of a sound signal to be associated with different spatial positions or sound qualities that may be more enjoyable to the listener.